The present disclosure relates generally to semiconductor chip packages, and more particularly to ring structures for chip packaging.
In semiconductor chip packages, where a semiconductor chip is mounted onto a substrate, the chip package may suffer from reliability issues when undergoing temperature cycling and/or during normal operation. Flip chip ball grid array, a type of chip package technology mounts the active side of the chip in an upside-down manner over the substrate and bonded to the same by means of a plurality of solder bumps attached to input/output pads thereon. Due to the inherent coefficient of thermal expansion mismatches between the chip and the chip package components, such as the substrate and underfill (an adhesive flowed between the chip and substrate), package warpage and thermal stresses are frequently induced in the chip package.
These high thermal stresses and warpage not only lead to the delamination in the low dielectric constant (low-k) interconnect layer(s) in the chip, but may also cause solder bump cracks leading to failure or degrading the long term operating reliability of the chip package. One method of reducing the warpage of the chip package is to attach a ring structure inside the package. However, even with the use of the ring structure inside the package, the package may still suffer from warpage to some degree. For example, warpage and therefore stress may still exist in a region of the chip package, such as at a central region of the package where the chip resides.